You'll need to buy the game in order to play, but then is free.
If you want you can get a VIP subscription that will grant you cosmetic items, but nothing that can give you an advantage over other players (just aestethic stuff).

I remember you can buy a vip membership as others have said. People voiced their concerns about the VIP veering into p2w territory and it was tailored backa little bit. They are really trying to level the play field between everyone including those who pay extra.